Sahih al-Bukhari Book 9, Hadith 44
My companions, who came with me in the boat and I landed at a place called Baqi .
The Prophet (ﷺ) was in Medina at that time. One of us used to go to the Prophet (ﷺ) by turns every night at
the time of the `Isha prayer. Once I along with my companions went to the Prophet (ﷺ) and he was busy in
some of his affairs, so the `Isha' prayer was delayed to the middle of the night He then came out and
led the people (in prayer). After finishing from the prayer, he addressed the people present there
saying, "Be patient! Don't go away. Have the glad tiding. It is from the blessing of Allah upon you
that none amongst mankind has prayed at this time save you." Or said, "None except you has prayed
at this time." Abu Musa added, 'So we returned happily after what we heard from Allah's Messenger (ﷺ) ."
Allah's Messenger (ﷺ) once delayed the `Isha' prayer and that was during the days when Islam still had not spread. The Prophet (ﷺ) did not come out till `Umar informed him that the women and children had slept. Then he came out and said to the people of the mosque: "None amongst the dwellers of the earth has been waiting for it (`Isha prayer) except you."
Allah's Messenger (ﷺ) disliked to sleep before the `Isha' prayer and to talk after it.